Network powered applications (e.g. +/−190Vdc or +/−130Vdc applications) are subject to voltage drop losses on the twisted wire pair cables (e.g. 22 AWG (American Wire Gauge)/24 AWG cables) that are typically used in telecommunications applications. The input power source is restricted to levels defined by the RFT-V (Remote powering Feeding Telecom-Voltage limited) specification. This restricts the input power source to maximum voltage, current and power levels (i.e. +/−190V (volts)+/−3%; 265 mA (milliamperes); and 100VA (volt amperes or 100 watts), respectively) thus restricting the total available loop length for higher powered applications.
Bellcore GR-1089-CORE provides certain centralized coordination standards for the regional Bell operating companies and does not permit direct paralleling of multiple power sources over respective telecommunication wires to supply power in excess of 100 VA. Moreover, paralleling of multiple twisted wire pair cables on a single loop increases costs and reduces the number of available wires in a single three-hundred (300) wire bundle. Paralleling of multiple twisted wire pair cables onto a telecommunications wirewrap pin is also prohibited. In order to optimize the system efficiency using a limited input power source and with traditional losses associated with a finite loop impedance, any remote unit in the system must be as efficient as possible in order to meet or exceed loop-length requirements from the power source.
Currently, there is no existing solution to mitigate the voltage drop on the twisted wire pair cables other than using more expensive, larger gauge wire or multiple twisted wire pair cables. Therefore, a closed-loop efficiency modulation technique within a remote device is needed to optimize the power efficiency in the entire loop, thereby reducing the required input current and associated voltage drop from the power source. This will allow the remote units/devices (e.g. SEMs) of the system to be placed farther from the input power source and will reduce the power dissipation inside the remote unit. In addition, this will increase reliability and reduce global hydro requirements.
Several technical terms will be used throughout this application and merit a brief explanation. A sealed expansion module (SEM) is a sealed enclosure that can be mounted in a variety of locations and protects a myriad of electronics equipment. An SEM is often a compact, sealed, full-service Internet Protocol (IP) access node for remote deployments in a network and may offer multiple very high bit-rate digital subscriber line (VDSL) ports.
An integrated circuit (IC) is a miniaturized electronic circuit having both semiconductor devices and passive components. An IC is manufactured in the surface of a thin substrate of semiconductor material and used in virtually any piece of electronic equipment.
An inter-integrated circuit (I2C) is a multi-master serial computer bus. It has a bi-directional two-wire design that utilizes a serial data line (SDL) and a serial clock line (SCL). The I2C bus is controlled by a master device that tells various slave devices when they are permitted to access the bus. For example, a digital-to-analog converter (DAC) could be a slave device accessed via the master device.
A DAC is a device that converts a digital signal (e.g. a binary code) to an analog signal (e.g. current or voltage).
A DC to DC converter is an electronic circuit that converts a source of direct current from one voltage level to another. This is done because many electronic devices that are supplied with external power or internal battery power contain multiple circuits that require different voltage levels than supplied by the external power source or internal battery.
An opto-isolator is a device that uses a short optical transmission path to transfer a signal between elements of a circuit (e.g. a transmitter and a receiver) while keeping them electrically isolated.
A bus or BUS is a common voltage rail used to power multiple nets/nodes within a power circuit. A communication protocol device is a computer bus. For example, but not by way of limitation, a communication protocol device may include a 1-Wire bus, HyperTransport bus, I2C bus, PCI (Peripheral Component Interconnect) Express bus, SPI (Serial Peripheral Interface) bus, or SMBUS (System Management bus).